1. Field of the Invention
This invention relates generally to needle administration sets for medical procedures involving the infusion or drainage of fluids and more particularly to safety guards for preventing inadvertent punctures from needles after completion of the medical procedure.
2. Background History
Medical treatments and procedures employing infusion and/or extraction of fluids through the use of needle administration sets have been common, routine procedures for many years. Such procedures are employed not only in conventional medical facilities such as hospitals, nursing homes and health care facilities but, in addition, it has become a fairly common practice for patients and family members in home environments.
Packaged sterilized administration sets generally included a sealed tubing length, capped at one end, and having a needle assembly at the other end. The needle assembly included a quill tipped hollow metal needle joined to a coaxial hollow thermoplastic base. The thermoplastic base included an integrally molded pair of transverse flexible wings. The wings were normally biased outwardly and generally coplanar.
In order to facilitate insertion of the needle tip into the patient, the wings were grasped and bent to face one another between the thumb and forefinger. Thereafter, the wings naturally sprung back to a coplanar orientation and were taped or secured to the user's skin to maintain the inserted needle assembly in position.
After the appropriate treatment of fluid infusion and/or drainage had been completed, the needle was withdrawn from the patient. Prior to disposal, it was necessary to recap the needle to prevent inadvertent punctures or needle sticks. Inadvertent needle punctures from used needle assemblies have been known to result in the contraction of highly contagious fatal diseases including the dreaded acquired immune deficiency syndrome.
The apparently simple task of recapping a needle has itself resulted in inadvertent punctures since the sharp tip of the needle had a tendency to contact the hand of a person attempting to recap the needle, especially if the needle was not positioned precisely coaxial with a hollow bore of a cap. This resulted from the fact that the user's hand, holding the cap, was moving in a direction toward the pointed tip of the needle.
One approach toward providing a safety sheath for needles of an administration set was shown in U.S. Pat. No. 4,820,282. This patent disclosed a sheath having generally planar base. Spaced from the base and extending parallel to the base was an upper wall. In use, the sheath was to be precisely aligned with the needle assembly such that the wings of the needle assembly were registered with the space between the base and the upper wall. Thereafter, the sheath was moved relative to the needle assembly, toward the tip of the needle. The sheath included a pair of retaining springs which extended into the space and the retaining springs were to deflect to permit the wings to pass and then snap back into the space behind the wings to lock the needle assembly within the sheath.
The device of U.S. Pat. No. 4,820,282 suffered from several inherent disadvantages, among them was the fact that the wings of the needle assembly had to be precisely aligned and registered with the space between the base and the upper wall. A further potential for difficulty in usage was presented by the springs which extended into the space. The springs had the potential for preventing the wings of the needle assembly from passing, and then locking behind the wings. This, of course, was a function of the material of which the needle assembly wings was fabricated and the force required to move the springs out of the path of the wings. Generally, the wings were fabricated of relatively soft, yieldable thermoplastic such that they may be readily bent and grasped for insertion of the needle.